In a wireless network, such as a network employing code division multiple access (CDMA) techniques, mobiles communicate with a base station. A mobile is any device suitable for communicating with a base station in the wireless network. For instance, a mobile might be a cellular phone, a personal digital assistant, or a laptop computer. A large amount of research has been performed to determine how to efficiently transmit data in the downlink direction, that is, from the base station to the mobiles.
There is not much research for the uplink direction, which is from the mobiles to the base station. This is true because, for cellular systems in particular, data flow has primarily been on the downlink. A base station needs to be able to transmit a lot of data to many mobiles. For instance, for a mobile that supports Internet capabilities such as browsing, a mobile being used to browse the Internet will receive much more data than what the mobile transmits. And voice information, which passes through the uplink, is a relatively small amount of information, particularly if the voice is compressed. Graphics-intensive Internet pages contain many times the amount of information as contained in normal compressed voice information.
However, mobiles are being created that not only transmit voice information on the uplink, but also transmit other information. For example, some new cellular phones allow digital pictures to be transmitted to the base station. It is expected that, as time progresses, the amount of information transmitted from mobiles to the base station will increase.
A need therefore exists for techniques that accommodate higher amounts of information from mobiles.